class_docstr: The operator is not really threadsafe as python cannot
  play with two locales at the same time. stop words
  should not be implemented here as the tokenization
  usually happens after this steps.
code: def _remove_stopwords(text, stops):  # type: ignore
      spl = text.split(" ")
      return " ".join(filter(lambda s: s not in stops, spl))
  
file_path: onnx/onnx/reference/ops/op_string_normalizer.py
imports: import locale
  import unicodedata
  import warnings
  import numpy
  from onnx.reference.op_run import OpRun, RuntimeTypeError
label_desc: Use image node_id 3 for calling the StringNormalizer obj's underlying member method code with example usage: obj._remove_stopwords(text, stops) and returns: str